Telephone-transmitter



(No Model.)

J; H; GHEEVER.

TELEPHONE TRANSMITTER.

Patented Jan; 22, 1-884.

' In ue 72/607? um nar. Wndlinglon. n. q

wire.

UNIT D STATES PATENT OFFICE.

JOSEPH H. oHEEvER, or SQMERVILLE, MASSACHUSETTS;

TELEPHONE-TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 292,203, dated January22,1884.

' Application filed June 25, 1883. (No modelJ i" 0 aZZ- whom it mayconcern.-

Be it known that I, JosEPH' H. OHEEVER, of Somerville,.in the county ofMiddlesex and State of Massachusetts, have invented certain Improvementsin Telephone-Transmitters, of which the following is a specification.

My invention relates to telephone-transmitters of that class commonlyknown as battery-transmitters, in which the variations in strength. ofan electric current flowing through a primary coil of wire, and avariable contact caused by the vibrations of a diaphragm, induce in aneighboring coil of wire alternating currents of an undulatorycharacter.

It consists in combining a microphone-transmitter with a coil diaphragmtransmitter, which latter instrument is described in an application ofmine filed February 5, 1883. In this instrument alternating andundulatory currents are induced in a secondary coil by the vibration ofan electrically-charged coil of wire fastened to a diaphragm placed inproximity thereto.

In the present invention I have combined in one instrument the inductiveeffects of the variation in current-strength in a primary coil upon asecondary coil with the. inductive effects of the bodily movement of aprimary coil upon a secondary coil. By coupling these inductive forces aconsiderable amount of current is caused to flow over the line-circuit,and loud effects are produced in the telephones connected therein,speech being transmitted with remarkable loudness and clearness.

The accompanying drawing, which forms a part of this specification, is asectional view of the instrument in its simplest form of construction.

F is a snitablewooden frame, having a mouthpiece, M, inserted in theupright portion there of. On the back of the upright portion is a recessor air-chamber, A. A diaphragm, D,

preferably of iron, covers this recess, and is fastened at its edge byscrews w to the frame F.

Attached by an insulating-cement to the diaphragm is a coil of insulatedwire, It, com= posed of one or more layers, and of a diameter nearlyequaling the diaphragm. This is shown in the drawing as being-made ofone layer of The'inside terminal of this coil is soldered to thediaphragm shown at m. The

tery. In the center of the diaphragm is fastened a button of metal orcarbon, 0. in electrical connection with the diaphragm.

Facing the coil R is a secondary coil of illsulated wire B, supported bya standard, N. This coil is made of a large number of convolutions offine wire well insulated, and wound on a wooden spool. The terminals ofthis coil are to be included in the line-circuit, shown as beingconnected with a hand-telephone, T. On the back of the secondary coil isfastened one of the primary electrodes, of which 19 is a carbon or metalbutton in loose contact with thebuttonc, and is fastened by a screw, a,to a spring, o, which spring is covered part of its length with rubbertubing, as is ordinarily done. The spring is secured to the spool by thescrew 8.

The operation of this telephone is as follows: On speaking into themouth-piece the diaphragm and primary coil R are thrown into vibration.The primary coil is constantly charged with electricity, the currentstarting from the battery Z passes over wire 3, through spring 4; andcarbon-button 12, through carbon 0 to diaphragm D, thence into the coilR at the internal contact an, and out by wire 4 to battery. With eachmovement of the diaphragm toward the'coil B there is an increase ofcurrent in the inducing-coil R due to an increase of pressure in thecontact-carbons, and with each movement in the opposite direction thereis a decrease of current in the said coil. By this increment anddecrement of current there are induced in the coil B alternatingcurrents of electricity. Thus it will be noticed that we have currentsinduced in the coil B' due to variation of the-electric current flowingin the coil R, and also currents inducedin the same coil due to thechange in' position of the coil B. These induced currents are similar incharacter, and combine together,

passing over the line-circuit 1 and 2, reproducing in the telephone Tthe sounds near or the speech uttered in the mouth-piece M. Thisarrangement of the primary and secondary coils is advantageous, inasmuchthat a greater amount of wire in the secondary coil may be exposed tothe direct influence of the primary coil.

I claim I The combination, in a transmitting tele This is- In testimony\vhereofll have signed my name to this specification in the presence oftwo sub- 10 scribing witnesses this 22d day of J une, 1883.

JOSEPH H. CHEEVER.

XVitnesses:

D. E. RICHARDS, GEO. WILLIS PIERCE.

